Transferability of cephalothin to the alveolar cavity in thoroughbreds

Five Thoroughbreds were classified into 4 groups according to the administr ation method used for saline solution (saline), ambroxol, and cephalothin s odium (cephalothin). In group A, cephalothin was injected intravenously aft er oral administration of ambroxol. In group B, cephalothin was injected in travenously after oral administration of saline. Groups C and D were used a s control groups. The dose of cephalothin or ambroxol was clinically admini strated. Venous blood and bronchoalveolar lavage fluid (BALF) were sampled from each group. In groups A and B, cephalothin concentrations in plasma re ached their maximum level 5 min after cephalothin administration and then d eclined over time. In plasma obtained from groups A and B, there were no si gnificant differences in pharmacokinetic parameters (T-1/2, Kel, Vd). By co ntrast, cephalothin concentrations in BALF reached their peak at 180 min af ter cephalothin administration in both groups A and B and maintained a rela tively high level even after 300 min. These findings indicate that cephatot hin requires a relatively long period of time to move from the blood stream to the alveolar cavity, but once transferred to the alveolar cavity, it is preserved for a long time. In groups A acid B, cephalothin concentrations in BALF were approximately at the same level. However, in group A, total pr otein in BALF was lower at 60, 180, and 300 min than the other groups. Then , cephalothin concentration was adjusted to total protein in BALF. After ad justment to total protein in BALF, group A showed a concentration level of cephalothin approximately 1.5-fold higher than that of group B. This sugges ts that the transferability of cephalothin to the alveolar cavity improves as a result of the oral administration of ambroxol.